### FILTERS ###
# Function that creates a firwin low-pass filter
def firwin_low_pass(input, fs, cutoff):
filter = firwin(5000, cutoff, fs=fs, pass_zero=True)
w, h = freqz(filter, worN=8000)
return [convolve(filter, input), w, h]
# Function that creates an FIR low-pass filter
def FIR_low_pass(input, cutoff):
FIR = cutoff * np.sinc(cutoff * np.arange(-200, 200))
FIR_windowed = np.multiply(FIR, get_window('hann', 400))
w, h = freqz(FIR_windowed, worN=8000)
return [convolve(FIR_windowed, input), w, h]
# Function that creates a butterworth low-pass filter
def butter_low_pass(input, fs, cutoff):
b, a = butter(12, cutoff / (fs / 2))
w, h = freqz(b, a)
return [lfilter(b, a, input), w, h]
# Function that creates a firwin band-reject filter
def firwin_band_reject(input, fs, cutoff):
filter = firwin(201, cutoff, fs=fs)
w, h = freqz(filter, worN=8000)
return [convolve(filter, input), w, h]
# Function that creates an FIR band-reject filter
def FIR_band_reject(input, center, width):
n = np.arange(-1000, 1000)
FIR = -2 * np.cos(np.pi * n * center) * width * np.sinc(width * n)
FIR[int(len(FIR) / 2)] += 1
FIR_windowed = np.multiply(FIR, get_window('hann', 1000 * 2))
w, h = freqz(FIR_windowed, worN=8000)
return [convolve(FIR_windowed, input), w, h]
# Function that creates a butterworth band-reject filter
def butter_band_reject(input, fs, cutoff):
cutoff = [cutoff[0] / (fs / 2), cutoff[1] / (fs / 2)]
b, a = butter(12, cutoff, btype='bandstop')
w, h = freqz(b, a)
return [lfilter(b, a, input), w, h]
# Function that creates a firwin high-pass filter
def firwin_high_pass(input, fs, cutoff):
filter = firwin(201, cutoff, fs=fs, pass_zero=False)
w, h = freqz(filter, worN=8000)
return [convolve(filter, input), w, h]
# Function that creates an FIR high-pass filter
def FIR_high_pass(input, cutoff):
FIR = -cutoff * np.sinc(cutoff * np.arange(-200, 200))
FIR[int(len(FIR) / 2)] += 1
FIR_windowed = np.multiply(FIR, get_window('hann', 400))
w, h = freqz(FIR_windowed, worN=8000)
return [convolve(FIR_windowed, input), w, h]
# Function that creates a butterworth high-pass filter
def butter_high_pass(input, fs, cutoff):
b, a = butter(12, cutoff, 'highpass', fs=fs)
w, h = freqz(b, a)
return [lfilter(b, a, input), w, h]
# Function that creates a firwin band-pass filter
def firwin_band_pass(input, fs, cutoff):
cutoff = [cutoff[0] / (fs / 2), cutoff[1] / (fs / 2)]
filter = firwin(200, cutoff, pass_zero=False)
w, h = freqz(filter, worN=8000)
return [convolve(filter, input), w, h]
# Function that creates an FIR band-pass filter
def FIR_band_pass(input, center, width):
n = np.arange(-1000, 1000)
FIR_case4 = 2 * np.cos(np.pi * n * center) * width * np.sinc(width * n)
FIR_windowed = np.multiply(FIR_case4, get_window('hann', 1000 * 2))
w, h = freqz(FIR_windowed, worN=8000)
return [convolve(FIR_windowed, input), w, h]
# Function that creates a butterworth band-pass filter
def butter_band_pass(input, fs, cutoff):
cutoff = [cutoff[0] / (fs / 2), cutoff[1] / (fs / 2)]
b, a = butter(5, cutoff, btype='band')
w, h = freqz(b, a)
return [lfilter(b, a, input), w, h]
